Surveying apparatus



April 20, 1954 w. H. D. HINCHMAN 2,675,627

SURVEYING APPARATUS Filed Aug. 28. 1951 3 Shegts-Sheet l CONTROL BOX PLUMB BOB INVENTOR. VVf/l/am H. D. H/bchmon 4TTORNIY8.

April 20, 1954 w AN 2,675,627

SURVEYING APPARATUS Filed Aug. 28. 1951 5 Sheets-Sheet 2 INVENTOR. W/Y/l'am H. D. flinch/nan ATTORNEYS.

Patented Apr. 20, 1954 UNITED STATES PATENT OFFICE SURVEYING APPARATUS William H. D. Hinchman, Detroit, Mich.

Application August 28, 1951, Serial No. 244,077

3 Claims.

This invention relates to surveying apparatus and more particularly to an apparatus for surveying hollow piling, that is, for determining the drift of the pilingfrom the vertical at various depths along the piling.

It is the object of this invention to produce a relatively simple device by which the angular deflection and displacement of hollow piling from the vertical can be determined quickly and accurately.

More specifically, the invention contemplates a plumb-bob in which is mounted a freely swinging pendulum. The pendulum is arranged within the plumb-bob such that, when the plumbbob is inclined at an angle to the vertical, the pendulum swings under the influence of gravity through the angle of inclination of the plumbbob in order to maintain its vertical position. The apparatus also contemplates a servo-mechanism which connects the pendulum with an indicator on a remotely positioned control box so that the deflection of the pendulum and the displacement of the piling from the vertical can be ascertained by readings on the indicator as ner in which the apparatus of this invention is 1 used.

Fig. 2 is a somewhat diagrammatic view of the operating mechanism within the plumb-bob and control box of the apparatus.

Fig. 3 is a top view of the plumb-bob.

Fig. 4 is a wiring diagram of the apparatus.

Fig. 5 is a vertical sectional view through the plumb-bob.

Fig. 6 is a view showing the face of the control box.

Fig. '7 is an enlarged fragmentary view of the dial and indicator on the face of the control box.

The apparatus of this invention generally includes a plumb-bob adapted tQ' bS lowered into a hollow piling II by means of a cable !2 from a tripod l3 positioned on the ground over the piling to be surveyed. An electric cable 54 connects the mechanism within the plumb-bob ID with the mechanism within a control box 15. The mechanism within plumb-bob l0 and control box I5 comprises a standard Selsyn generator-motor system, Selsyn systems of this type being generally described in the article entitled "Selsyn Design and Application by'T. C. John son in Trans. AIEE, volume 64; page '7 03. I The plumb-bob is preferably fashioned as a housing formed of two cylindrical half sections l 6 and I1, one forming the top half of the plumbbob and the other formin the bottom half. The lower housing section I! is provided with a bumper I8 at its lower closed end and with a circumferential collar l9 around its upper opened end so that the lower section I! can be slipped upwardly into frictional engagement with the upper housing section it. Within housing section Hi there is secured several circumferentially spaced brackets 20. Brackets are secured to the side wall of section It and extend generally vertically of the plumb-bob. These brackets are provided with inwardly extending ears 2! and 22 at the upper and lower ends thereof. A supporting plate 23 is mounted on the ears 2| as by screws 24, and another supporting plate 25 is supported on the cars 22 by screws 26. The brackets 29 and plates 23 and 25 form a frame secured to the upper housing section IS on which the operating mechanism within the plumb-bob is supported.

For the purposes of illustration the operating mechanism within the plumb-bob is shown as a Selsyn motor 30 suspended from plate 23 as by screws 3| and having a rotor 32, the shaft 33 of which extends vertically of the plumb-bob and is journalled adjacent its lower end within a bearing 34 supported on plate 25. The lower end of shaft 33 is threaded to receive a pair of nuts 35 between which is clamped a support bracket 36 which in turn supports a Selsyn transmitter 31. Transmitter 31, it will be observed, is arranged to rotate with shaft 33 in a plane perpendicular to the vertical axis of the plumbbob. The rotor shaft 38 of transmitter 31 extends perpendicularly to shaft 33 and has fixedly supported thereon a pendulum 39 in the form of a bushing 40 having a depending arm M which carries a weight 42 at the lower end thereof. A set screw 43 fixes bushing 40 on shaft 38 so that shaft 33 is caused to rotated in correspondence with the swinging of pendulum 39. The extent to which pendulum 38 is permitted to swing is limited by a stop 44 in the form of a cup supported on a plate 45 which is in turn suspended from plate 35 by threaded rods 46.

As is shown in Fig. 1, plumb-bob It is arranged to be lowered. into the driven hollow piling; and as the piumb-bcb reaches a location Where the piling is displaced from the vertical, the housing It engages the side wall of the piling so that the plumb-bob assumes a position tilted in correspondence with the inclination of the piling at the plumb--bob location. It has been found that a plumb-bob housing 56, I1 measuring about six inches in diameter and four feet in length is sufficiently large to house the necessary mechanism therein and to produce very accurate results.

Within the control box l5 there is arranged a selsyn generator i? and a selsyn indicator 48. The rotor shaft ie of generator 4'! extends outwardly through the front face 50 of control box and has a knob 51 secured thereto. Knob 5! has a scale 52 around the periphery thereof which cooperates with a fixed indicator 53 on the face 50 of control box i5 for designating the angular position of shaft 39. Selsyn indicator 48 hasa rotor shaft 54 to the end of which is: secured a pointer 55 which cooperates with a dial 56 on the face 50 or" box IE to designate the angular position of shaft 5:2,

Referring now to the wiring diagram illustrated in Fig. 4, it will be observed thatthe'generator El and indicator 18 in control box iii are connected respectively with motor 38 and transmitter 37 the plumb-bob it by means of a conventional selsyn generator-motor hookup. The generator l? has a single phase primary winding on its rotor which is connected: by conductors. 5-8 and 53 in cable M with the'primary winding 6-3 on the rotor 32 of motor 30. The stator 61 of generator t? has three secondary windings. 52. Each of the windings 62 of generato 4 is connected with corresponding secondary windings 53 on the stator fi l of motor 30 by conductors 65, E5 and 67.

The primary winding ill on the rotor of indicator i8 isconnected by conductor H and 12 with the ends of the primary winding it on the rotor f the transmitter 3 in plumb-bob l9. Likewise, the three secondary windings M on the stator of indicator 4% are connected with'threeacorresponding windings F5 on the stator of transmitter 3-? by conductors i5, i3 and it;

The apparatus; is adapted to be energized by connection with a standard source of H9 volts A. C.v Accordingly, control box 15 i provided with a socket it having a pair of conductors 89 and ti for energizing the primary windings of the selsyn devices. Conductor 83 connects through a fuse S2 with the movable arm 83 of a power switch 84% having an offcontact 85 and a series of on contacts 3%, 8! and 88. Contactv 88 is connected directly with a conductor 8:9 which connects with the conductor 58 of rotor 51 as at Contacts e and 8? are connected with conductor through a resistance.v S l. The other rotor conductor 52 connects with inlet conductor ti as at A pilot light 93 on the face of: cone trol cox if; is connected across conductors B9 and so that, when switch 83 is turned; to the on position, pilot light 93 isilluminated.

Rotor 'iil of indicator 38 is energized through a transformer coil 53 which is connected across conductors. 5t and 53 by conductors 95am! 96;

hus, when socket 7; is connected with a source of current and, switch 85 is turned on, the rotor wi dings it? and W are excited and the excitation of these windings induces, by transformer action, voltages in the secondary windings 52; 53, i i and l5. 7

It will he observed that with this arrangement, whenever there is a lack of correspondence in position between'the-rotor 51 and the rotor Bil, the voltages in the stator windings 52 and 63 will become unequal, thus causing a current to circulate in the secondary winding. 53 which produces a torque on the rotor se causing the rotor fifl-to rotate to a position in correspondence with the generator rotor 51. Likewise, when there is a lack of correspondence in position between rotors l3 and 10, current circulates in windings it of indicator 48 which causes the rotor ill to rotate to a position in correspondence with the rotor 73. This operation is in accordance with the generally well-known principle of operation of selsyn motors.

In order to enable ascertaining the rotative position of plumb-bob" til while it is suspended at a considerable depth within the piling, the plumb-bob housing it, i7 is provided on the upper end thereof with a pair of orientation lights 91 which are connected by conductors 98 and 99 across conductors 58 and 59 so that, when switch 83' is turned on, the orientation light iii are illuminated.

When it is desired to survey a hollow piling which is driven into the ground to a considerable depth, plumb-bob i9 is lowered into the piling at predetermined increments of depth, for example, increments of ten feet. At each location, with the switch 8% turned on, the generator control knob 5| is rotated until the indicator needle 55 shows a maximum angular deflection. As the control knob 58- is rotated, rotor 51 rotates with it; and by reason of the servomechanism arrangement of generator 4? and motor 30, rotor 39- together with its shaft 33 is caused to rotate in correspondence with the rotation of genera.- tor knob 52. If, at the location being surveyed the piling i i isi'nclined to the vertical, the plumb- =boo it, lying against the wall of the piling, is also'inclined; and rotor shaft 33 is correspondingly inclined, since the axisoi shaft 33 isaligned with the axis of the plumb-bob. When shaft 33 is rotated, transmitter 3?, with its rotor shaft 38, is revolved in a plane perpendicular to shaft 33' andpendulum S'sswings under the influence of gravity to the vertical position on. a plane perpendicular to the plane of inclination ofthe plumb-bob, thereby causing the shaft 33 to rotate an amount proportional to the extent to which pendulum 39 swings in maintaining its vertical position. For example, if the piling H at the location being surveyedis inclined to the vertical at an. angle of 15, then it is obvious that shaft 33 will also be inclined to the vertical at an. angle of 15. If shaft 33 is rotated through 360, then pendulum 39 will swing with respect to the vertical 15, first in one direction and then in the opposite direction under the influence of gravity in maintaining av vertical position.- It the pendulum 39=swings through an angle of 15,

shaft 33 will be rotated through 15 and the pointer 55 will likewise rotate. through an angle of 15 and designate this angle of rotation on scale 55.- After the operator adjusts the generator knob 5| to a position where the indicator needle 5.5'shows a maximum angular deflection, the generator control, knob. 51 is, rotated through 180 to obtain. the maximum angular deflection in the opposite direction. The average of these twomaximum readings is the angular deflection of the piling at the depth to which the plumb,- bob is. lowered. Since the depth to which the plumb-bob is lowered can be ascertained, such as by suitable markings on the cables I2 or it, the angular deflection of, the pilefcan be con.- verted to. linear displacement of the. pile for. that particular depth.

' After themaximum angular deflection read.- ings on dia1f55 at one'locati'on are noted, the

plumb-bob islowered-to a new depth, for instance.

5 knob 5| is again turned as above described and the two maximum angular deflection readings on dial 5B are noted at each location. Thus, the total displacement of the pile at any depth may be easily calculated; and by observing the orientation of lights 91 at the upper end of the plumbbob, the direction in which the piling is inclined can be determined, since the zero mark on scale 52 of knob 5| bears a fixed relation to the position of lights 97.

Although the plumb-bob is described in connection with surveying hollow piling, the device is admirably suited for use in numerous other surveying applications. For example, the arrangement described herein may be employed for determining the course of travel of pipes in general that are driven into the ground, pipes for oil wells being illustrative. The device is also useful for surveying the elevation of horizontal pipes lying on the bottom of bays or oceans to determine their contour and for registering the inclination of relatively high self-supporting structures such as radio towers, chimneys, and smokestacks, etc.

I claim:

1. A device for surveying hollow piling comprising a plumb-bob adapted to be lowered into the piling being surveyed and engage the side wall of the piling such that the vertical axis of the plumb-bob is inclined to the vertical to the same extent as the vertical axis of the piling at the plumb-bob location, a selsyn motor in said plumb-bob, a shaft in said plumb-bob rotatable about an axis parallel to the vertical axis of the plumb-bob, said shaft having a driving connection with the rotor of said selsyn motor, a selsyn transmitter supported by said shaft for rotation therewith, said selsyn transmitter having a rotor shaft arranged for rotation about an axis perpendicular to the vertical axis of the plumbbob, a pendulum fixed on said transmitter rotor shaft whereby, when said plumb-bob is inclined to the vertical, the rotor of said selsyn motor can be rotated to position the rotor shaft of said transmitter parallel to the plane of inclination of the plumb-bob and thereby permit the pendulum to pivot to a vertical position, a remotely p0- sitioned selsyn generator coupled with said selsyn motor, a manually movable indicator connected with the rotor of said selsyn generator for indicating the rotative movement of said last mentioned rotor and the corresponding rotative movement of the rotor of said selsyn motor, a second selsyn motor positioned remotely of said plumb-bob and coupled with said selsyn transmitter, said second mentioned selsyn motor having an indicator associated with the rotor thereof for indicating the rotative position of said last mentioned rotor in correspondence with the rotative position of said pendulum and the retor shaft of said transmitter whereby, when the plumb-bob is disposed in a position such that its vertical axis is inclined to the vertical and said manually movable indicator of said selsyn generator is operated to rotate the rotor shaft of said first mentioned selsyn motor, said pendulum pivots from a position parallel to the vertical axis of the plumb-bob to a vertical position, and the angle through which the pendulum pivots is designated by said indicator of said second mentioned selsyn motor.

2. The combination set forth in claim 1 wherein said first mentioned shaft comprises the rotor shaft of said first mentioned selsyn motor.

3. The combination set forth in claim 1 wherein said plumb-bob comprises an elongate casing of cylindrical shape and including a pair of orientation lights mounted on the upper end of said casing.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 1,551,393 Hewlett et a1 Aug. 25, 1925 1,746,562 Souvitza Feb. 11, 1930 1,928,970 Johnston Oct. 3, 1933 2,429,620 Harrington Oct. 28, 1947 2,477,574 Braddon Aug. 2, 1949 2,497,594 Fialkow Feb. 14, 1950 

